1. Field of the Invention
This invention relates to a vehicle seat slide device and more particularly to a power seat slide device used for a vehicle seat.
2. Statement of the Prior Art
Generally, a power seat slide device for a vehicle seat uses a screw and nut assembly for sliding and holding the seat. Further, such a screw and nut assembly is disposed between the outer and inner rails of the device, which makes the whole device complicated and causes a possibility of cutting the wire harness for the power supply source. Furthermore, due to the location of the screw and nut assembly, the device requires excessive length in the front and rear direction of the vehicle, which causes a problem of limiting the space available for an occupant of the rear seat.
Improvements have been made to obviate the above drawbacks. One such improvement is shown in a Japanese Patent Publication No. 57-47225, in which the screw and nut assembly has been housed in the rail itself. This prior art assembly, however, has to house the gears of the gear box in addition to the screw and nut assembly and the rail (upper rail) must be made large enough to house the assembly. Further, this prior art assembly uses a roller for sliding, which may cause a problem for smooth sliding which has not yet been realized.